A surface acoustic wave convolver, excited by an appropriate reference, can correlate a signal waveform only if the signal arrives within a small time interval such that the signal and the dynamic reference simultaneously pass one another within the parametric region of the device. The concept described herein demonstrates that the reference waveform can be combined with the signal waveform in a manner to yield the complete correlation function independent of the time of arrival of the signal, thereby permitting asynchronous operation. Doppler components are automatically rejected with no compromise to the desired correlation.
The self synchronizing convolver system may be utilized, for example, in spread spectrum radars, coherent repeaters, and in spread spectrum communications. It efficiently permits asynchronous operation. It also permits a relatively economical correlator to be developed. In its simplest form, only two input ports and one output port are required.